PHPユーザー登録ログインシステム登録処理ページ

<?php session_start(); //注册处理界面 regcheck.php if(isset($_POST["hidden"]) && $_POST["hidden"] == "hidden") { $user = trim($_POST["username"]);//trim()函数移除字符串两侧的空白字符 $psw = md5(trim($_POST["userpwd"])); $psw_confirm = md5(trim($_POST["confirm"])); $code = $_POST["code"]; if($user == "" || $psw == "" || $psw_confirm == "") { echo "<script>alert('请确认信息完整性！'); history.go(-1);</script>"; } else if($code != $_SESSION[' ver_code']){ echo "<script>alert('验证码不正确，请重新输入！'); history.go(-1);</script>"; } else { if($psw == $psw_confirm) { $conn = mysqli_connect("localhost","root","root"); //连接数据库,帐号密码为自己数据库的帐号密码 if(mysqli_errno($conn)){ echo mysqli_error($conn); exit; } mysqli_select_db($conn,"userdb"); //选择数据库 mysqli_set_charset($conn,'utf8'); //设定字符集 $sql = "select username from user where username = '$user'"; //SQL语句 $result = mysqli_query($conn,$sql); //执行SQL语句 $num = mysqli_num_rows($result); //统计执行结果影响的行数 if($num) //如果已经存在该用户 { echo "<script>alert('用户名已存在'); history.go(-1);</script>"; } else //不存在当前注册用户名称 { $ip=ip2long($_SERVER['REMOTE_ADDR']); // 把ip地址转换成整型 $time=time(); $sql_insert = "insert into `user` (`username`,`userpwd`,`createtime`,`createip`) values('" . $user . "','" . $psw ."','".$time."','".$ip."')"; $res_insert = mysqli_query($conn,$sql_insert); if($res_insert) { echo "<script>alert('注册成功！');window.location.href='login.php';</script>"; } else { echo "<script>alert('系统繁忙，请稍候！'); history.go(-1);</script>"; } } } else { echo "<script>alert('密码不一致！'); history.go(-1);</script>"; } } } else { echo "<script>alert('提交未成功！');</script>"; } ?>